Detection of pathogenic Leptospira with rapid extraction followed by recombinase polymerase amplification (RPA) and quantitative polymerase chain reaction (qPCR) assay-A comprehensive study from Sri Lanka.

Leptospirosis is the most widespread zoonosis in the world. The disease is more prevalent in tropical regions where the majority of developing countries are located. Leptospirosis is considered a protean manifestation zoonosis with severity of the disease ranging from a mild febrile illness to a severe and life-threatening illness. Clinical symptoms of leptospirosis overlap with other tropical febrile illnesses. Early, rapid, and definitive diagnosis is important for effective patient management. Since Polymerase Chain Reaction (PCR)-based assays are not readily available in most clinical settings, there is a need for an affordable, simple, and rapid diagnostic test. Quantitative PCR (qPCR) and Recombinase Polymerase Amplification (RPA) were implemented at the Faculty of Medicine, University of Kelaniya, and a prospective study to evaluate RPA for diagnosis of acute phase of leptospirosis was conducted. Results indicate that RPA and qPCR were positive in 81% (98/121) of the total positive and acute clinical samples. Of the 81 positive MAT confirmed patients 60 (74%) and 53 (65%) were positive with qPCR and RPA respectively. Retrospective evaluation revealed a high diagnostic accuracy (sensitivity-70% and specificity-87%) of RPA compared to MAT as the reference gold standard. Results further suggest that there is no significant difference between the two assays, qPCR and RPA-SwiftX (P = 0.40). Laboratory procedures for the extraction and detection by qPCR in the laboratory have been optimized to obtain results within 6 hours. However, the RPA-SwiftX method under field conditions took 35 minutes. The RPA-SwiftX method could replace the qPCR which shows similar sensitivity and specificity. Therefore, RPA established under the current study presents a powerful tool for the early and rapid diagnosis of leptospirosis at point-of-care.

Postinfectious Acute Cerebellar Syndromes in Children: A Nationally Ascertained Case Series From Australia 2013-2018.

INTRODUCTION: Postinfectious acute cerebellar syndromes show a wide spectrum of acute severity and can occur with acute febrile illness or vaccine receipt. Varicella has historically been the most common cause, associated with up to 25% of cases in large cohorts. This study aimed to describe the spectrum of syndromes in a setting with high varicella vaccine coverage. METHOD: Data were collected on children initially identified as "suspected encephalitis" subsequently designated "not-encephalitis" at participating children's hospitals in the Paediatric Active Enhanced Disease Surveillance (PAEDS) network, Australia, as part of the Acute Childhood Encephalitis study. A comprehensive descriptive analysis was undertaken on prospectively identified, national series of children with postinfectious acute cerebellar syndromes from 2013 to 2018. Cases were classified using a previously validated severity score, and the outcome was assessed at 12 months using the Liverpool Outcome Scale score. RESULTS: A total of 20 cases (65% were vaccinated for varicella) were included, of which 70% were subcategorized as acute cerebellar ataxia (ACA), 20% acute cerebellitis (AC), and 10% acute fulminant cerebellitis (AFC). An acute febrile illness was noted in 55% and none were related to varicella or were temporally related to varicella vaccination or other childhood vaccines. A subset (total of 7 children) followed up at 12 months all showed reduced Liverpool Outcome Scale scores. DISCUSSION: The study provides an overall description of this uncommon spectrum of neurologic syndromes and shows the infrequency of varicella zoster virus as a cause in a vaccinated population.